The invention relates to a calibration device.
Calibration devices are used, for example, for calibrating extruded continuous profiles, in particular tubes. Plastic melt is hereby initially prepared in an extruder and shaped by an exit nozzle. To assure the desired dimensioning of the continuous profile, the latter travels through the calibration device after the shaping operation for providing precise size thereof.
Up to some time ago, the production of plastic tubes required the availability of various calibration devices for different wall thicknesses or outer diameters. Hereby, the tools needed to be replaced, requiring a shutdown of the machine which leads to downtimes.
DE 198 43 340 C2 thus proposed to use an adjustable calibration device for different tube dimensions. This calibration device includes a plurality of lamellae which are distributed in spaced-apart relationship about the circumference on the outer sides of the tube to be sized. Viewed in production direction of the tube, a plurality of such lamellae rings is disposed within a calibration station, with the individual lamellae of the individual lamellae rings positioned with clearance to thereby permit easy adjustment of the lamellae of the individual rings in relation to the lamellae of the subsequent ring or the preceding ring. The lamellae are united in segments to form a lamellae block and supported by a holding structure. The holding structure in turn is connected to the housing for radial adjustment.
A problem of this construction of the calibration device is however the single-piece configuration of the holding structure. It has been shown during production of the calibration device that part of the holding structure, namely the adjustable part, must be first inserted in the housing. Then, the individual lamellae are secured to the support and holding structure in a manner that is difficult to implement.